Biosealing

Abstract

The invention relates to a method to repair a leak in a geological structure or a construction comprising a geological material, comprising administering a liquid nutrient composition, comprising an energy source for anaerobic bacteria and a multivalent metal ion upstream of the leak allowing micro-organisms present in the structure or construction to ferment the energy source and to grow, thereby increasing biomass in and/or around the leak releasing mineral particles upstream of the leak allowing the mineral particles to migrate to the leak; and allowing the mineral particles to settle in the biomass.

1. Method to repair a leak in a geological structure or a construction comprising a geological material, comprising
 administering a liquid nutrient composition comprising an energy source for anaerobic bacteria and administering a liquid comprising a multivalent metal ion, which may be the same as the liquid nutrient composition, upstream of the leak, wherein the liquid nutrient composition and the liquid comprising the multivalent metal ion flow towards the leak with ground water flow, 
 allowing micro-organisms present in the structure or construction to ferment the energy source and to grow, thereby increasing biomass in and/or around the leak 
 releasing mineral particles upstream of the leak 
 allowing the mineral particles to migrate to the leak; and 
 allowing the mineral particles to settle in the biomass. 
 
     
     
       2. Method according to  claim 1 , wherein the nutrient composition comprises an organic energy source and a nutritional anion, wherein the anion is preferably an nutritional inorganic anion, more preferably selected from the group consisting of nitrates, phosphates and combinations thereof. 
     
     
       3. Method according to  claim 1 , wherein the mineral particles are released in situ by administering a salt solution, comprising a monovalent cation, in an effective amount to release the mineral particles from the geological material. 
     
     
       4. Method according to  claim 3 , wherein the salt solution comprises at least one monovalent cation selected from sodium ions and potassium ions. 
     
     
       5. Method according to  claim 3 , wherein the concentration of the salt of the monovalent cation is in the range of 0.5 to 10 g/l, preferably 0.8 to 5 g/l. 
     
     
       6. Method according to  claim 1 , wherein the density of the nutrient composition, the liquid comprising the multivalent metal ion and/or the salt solution for releasing mineral particles is about the same as the density of the groundwater within the hydrological influence area. 
     
     
       7. Method according to  claim 1 , wherein the energy source content of the nutrient composition is 0.02 to 5 wt. %, in particular 0.2-5 wt. %. 
     
     
       8. Method according to  claim 1 , wherein the multivalent metal ion concentration of liquid comprising the multivalent metal ion is 0.1 g/l to 5 g/l. 
     
     
       9. Method according to  claim 1 , wherein the multivalent metal ion is selected from the group consisting of calcium ions, magnesium ions and iron ions. 
     
     
       10. Method according to  claim 1 , wherein the nutrient composition comprises at least one organic nutrient component selected from carbohydrates (in particular glucose, glucose containing sugars, glucose containing oligosaccharides and glucose containing polysaccharides) amino acids, (poly)peptides (in particular proteins) and organic acids. 
     
     
       11. Method according to  claim 1 , wherein the viscosity at 12° C. of the nutrient composition, the liquid comprising the multivalent metal ion and/or the salt solution comprising the monovalent cation is 10 mPa·s or less. 
     
     
       12. Method according to  claim 1  wherein the geological structure or the construction comprises at least one component selected from the group consisting of gravel, clay, sand, silt, peat and fractured or jointed rock formations. 
     
     
       13. Method according to  claim 1  wherein the structure or construction is selected from the group consisting of dams, dykes, tunnels, subterranean parking's, basements, sheet pile walls, diaphragm walls, remembrance, constructions, sewers and (natural connections between different) aquifers. 
     
     
       14. Liquid nutrient composition for bacteria in a geological material, comprising
 water 
 at least one organic energy source selected from carbohydrates, amino acids and peptides in a total concentration of 0.2-50 g/l; 
 at least one multivalent metal ion selected from magnesium ions, calcium ions and iron ions in a total concentration of 0.1 to 5 g/l; 
 at least one nutritional anion, preferably selected from nitrates and phosphates, in a total concentration of 0.1 to 8 g/l; and 
 at least one organic acid in a concentration of 0.1 to 2 g/l. 
 
     
     
       15. Use of a liquid nutrient composition as defined in  claim 14  for reducing water permeability of a geological structure or a construction comprising a geological material. 
     
     
       16. Use of a composition comprising a salt of a monovalent cation, such as defined in  claim 14  to mobilise mineral particles in a geological structure or a construction comprising a geological material. 
     
     
       17. Use of a liquid comprising a multivalent metal ion, such as defined in  claim 14  to immobilise mineral particles in a geological structure or a construction comprising a geological material.